1. Field of the Invention
The invention relates to a swash plate type compressor with a variable displacement which is particularly suitable as a refrigerant compressor for an automotive air-conditioning apparatus.
2. Description of the Prior Art
A swash plate refrigerant compressor with a variable displacement mechanism suitable for use in an automotive air condition system is disclosed in U.S. Pat. No. 4,963,074. As disclosed therein, the swash plate is supported on a rotatable shaft of the compressor. The swash plate is fixedly supported on the rotatable shaft through a single hinge coupling mechanism. More particularly, the hinge coupling mechanism of the '074 patent includes a projection extending from the swash plate and an axial slit formed in the projection. A planar plate portion, which is mounted on the drive shaft, aligns with the slit. A pin extends from the projection portion of the swash plate and penetrates the planar plate portion.
One of the disadvantages of the of the '074 compressor is that a large axial force acts on the single hinge coupling mechanism, thereby causing excessive wear between the outer peripheral surface of the pin and slit. As a result of this wear and deterioration of the hinge coupling mechanism, capacity control of the compressor is adversely affected and adjustment of the piston stroke becomes less accurately controlled.
Another prior art swash plate compressor is shown in FIGS. 1 and 2. There, first arm potion 27d of swash plate 27 and second arm portion 27c are symmetrically disposed with respect to the center of swash plate 27. First arm portion 27d is coupled to projection 30a of first rotor plate 30 through pin 37b. Second arm portion 27c is coupled with projection 29a through pin 37a. Pins 37a, 37b are fixed in position by snap rings. While two hinge coupling mechanisms support swash plate 27, as seen in FIG. 2, the hinge coupling mechanism requires several parts, e.g., arms 27c, 27d, pins 37a, 37b, snap rings 48, etc., to effect the hinged coupling. Consequently, the intricacy, and potentially the cost, of the compressor is increased by the number of parts comprising the hinge coupling mechanism.